The main differences between these two versions are the two new services provided in JOnAS 2.4.4: registry and tomcat.
jonas.services jmx, security, jtm, dbm, resource, jms, ejb
jonas.services registry, tomcat, jmx, security, jtm, dbm, resource, jms, ejb
jonas.service.registry.class org.objectweb.jonas.registry.RegistryServiceImpl
jonas.service.registry.mode automatic
jonas.service.tomcat.class org.objectweb.jonas.tomcat.EmbeddedTomcatImpl33
jonas.service.tomcat.args